JPH10126429A - Network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of a fault by surely detecting a duplicated address so as to send fault information to a system without sacrificing the transmission efficiency and giving hindrance to normal communication. SOLUTION: A station desiring a new subscription decides a wait time till a subscription request frame is sent after a new subscription request takes place in its own station by using a random number, and sends the subscription request frame after the lapse of the wait time. Furthermore, each station stores its own rising time and adds the rising time of its own station to the subscription request frame when the new subscription desiring station sends the subscription request frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network in which data communication between stations is performed based on a logical ring formed by a plurality of subscriber stations.

[0002]

2. Description of the Related Art Conventionally, when a network is started, a plurality of stations transmit and receive many frames at the same time to perform a subscription operation. As a result, if two stations with overlapping addresses try to join at the same time, or if addresses overlap due to physical connection of two networks, both stations monitor each other for overlapping addresses. Therefore, when the duplication of the address is detected, both are dropped from the logical ring. In addition, each station (agent) configuring the logical ring notifies the specific station (manager) that collects information on a one-to-one basis when an abnormal cause occurs. In each constituent station, a manager station to be notified is set in advance by an administrator.

[0003]

However, the conventional network has the following problems. (L) When two stations transmit the join request frame at the same time, if the transmission interval is set to be the same, the transmission timing is synchronized and both stations simultaneously detect the address duplication. Can't join permanently. Further, transmission / reception processing is performed at a high frequency, which increases not only the communication processing load of each station but also the load of the transmission path. (2) In general, when address duplication occurs, the station that is performing stable communication for a long time should continue operation with priority. In the conventional method, in a situation where a duplicate station can exist at the same time (connection between networks, etc.), all the stations are dropped. Therefore, a station that has normally communicated from the beginning of the system operation is dropped, and normal communication is hindered.

(3) In order to notify abnormal information, it is necessary for an administrator to specify a station and store it in a file of each station. In addition, if a frame is lost by notifying only once when a factor occurs, an abnormality may not be transmitted. This is a major drawback in systems that prevent the network from falling into serious trouble. Therefore, an object of the present invention is to reliably detect address duplication and transmit the abnormal information to a system without sacrificing transmission efficiency and without hindering normal communication, thereby preventing occurrence of a failure. It is.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is a network for performing data communication between each subscribed station based on a logical ring constituted by the stations subscribed to the network. In the case where a joining request frame is transmitted from a station desiring to newly join to an already joined station via a network, the address of the already joining station receiving the joining request frame is the same as the address of the joining desired station. In a network in which an abnormal response frame is returned from an existing joining station to a joining requesting station and the joining request is rejected, a station requesting a new joining sends a joining request frame. When transmitting on the network, the standby time from when a new subscription request is issued to the own station until transmission of a subscription request frame is determined by using a random number. After a lapse of waiting time to transmit the subscription request frame.

According to a second aspect of the present invention, there is provided a network for exchanging data between the subscribed stations based on a logical ring constituted by the stations subscribing to the network. If the address of the joining station that received the joining request frame is the same as the address of the station that wants to join, when it is determined that the address is the same, In a network in which an abnormal response frame is returned from an existing joining station to a joining requesting station to reject the joining, the start-up time of the own station is stored for each station, and the new joining requesting station transmits a joining request frame. In this case, the start time data of the own station is added to the frame and transmitted. Also,
If the address of the already-subscribed station that has received the join request frame is the same as the address of the desired station, the start-up time of the already-subscribed station is compared with the start-up time of the desired station. If the start time is before the start time of the desired station, an abnormal response frame is returned from the existing station to the desired station, and if the start time of the existing station is after the start time of the desired station, the abnormal response frame is returned. The subscriber station leaves the logical ring of the network.

According to a third aspect of the present invention, in the first or second aspect of the present invention, when an error in address duplication between a station desiring to join and an existing station and an abnormality in a transmission line are detected, the content of the abnormality is determined. Based on this, an abnormality notification frame is created, and broadcast transmission is performed at a constant period until the detected abnormality is resolved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing the overall operation of the embodiment of the present invention. As shown in the figure, at the time of ring joining, the transmission interval of the addition request frame of each station is dispersed using random numbers with the system time at the time of starting the station as an initial value (S1, S2). Next, after monitoring the line for a certain period of time for transmission of the addition request frame, the subscriber joins (S
3-S8). Prior to the joining process, each station records its system time in an internal file when the station starts up. The constituent stations set the time of the file in the “station start-up time” area provided in the frame and perform broadcast transmission at a fixed cycle.

When the source address of the received frame and the address of the own station match, the information of the "station start time" area provided in the received frame is compared with the start time of the own station, and the link is established. Determine if you want to continue or drop out.
The determination is that the local station is to be continued when “partner station time> local station time” and that the local station is to be dropped when “partner station time ≦ local station time”. By performing the same determination process by each station, the station that has operated first continues to communicate between the overlapping stations, and the station that wants to join later drops out.

Next, when an abnormality occurs, all the constituent stations set the cause of the abnormality in the abnormality notification frame and notify each constituent station by broadcast transmission. At the same time, a fixed-period timer is started, and an abnormality notification frame is transmitted each time up. When the cause of the error is removed, the timer stops. Thereby, the constituent station receiving the abnormality notification frame recognizes the occurrence of the abnormality factor and the factor, and at the same time, starts a timer that sets a different time for each factor. Here, when the same frame is received again, the timer corresponding to the cause of the abnormality is reset. Next, when the time is up, the cause of the abnormality of the timer is released. When each station starts the above-described reception analysis processing, each station can recognize an abnormality in the entire system.

FIG. 2 is an explanatory diagram showing an embodiment of the first aspect of the present invention. Each station is connected by FDDI, implements a broadcast transmission function, and records the start-up time of each station in a file. The operation of joining the logical ring is broadcast three times (randomly changing between 100 and 500 msec) by transmitting a join request frame, and if there is no abnormal response for 2 seconds, join. In addition, if it is specified that a subscription is not made if an abnormal response frame (broadcast transmission) is received, each station transmits a subscription request frame at a different cycle, so that other stations transmit subscription request frames at different timings. The received address is checked for duplication of addresses.

[0012] In the figure, since there is an already-subscribed station and a desired subscribed station which is address 2, when a subscribe request frame is broadcast-transmitted from the desired subscribed station at address 2, the previously subscribed station at address 2 receives it. Then, an overlap with the address 2 of the own station is detected, an abnormal response frame is created, and broadcast transmission is performed. This is received by the station desiring to join at address 2 and abnormal processing is executed, so that participation in the logical ring is interrupted. Unless an abnormal response frame for the own station is received, the stations desiring to join other addresses 1 and 3 are joined to the logical ring after a response monitoring time of 2 seconds has elapsed.

FIG. 3 is an explanatory diagram showing an embodiment of the second aspect of the present invention. Each station is connected by FDDI, implements the same address duplication judgment processing as the broadcast transmission function, and sets the start time of the station. Are recorded in each file. Each station is divided into two networks FDDI1 and FDDI2, and when both are combined, there will be an A station and a B station having the same address 3 (eg, IP address) in each network. . Therefore, each station sets a time recorded in advance in a start-up time area in a frame (PDU / UDP / IP) and transmits the frame.

A station that receives these frames compares the source IP address of the frame with its own IP address, and when a match is detected, the information of the “station start-up time” area in the received frame and the station itself are compared. Compare the start-up times of the stations. In the case of the station A, "the partner station time (5:00)> the own station time (1:00)" is satisfied, and since the station A has been operating before the station B, the priority is recognized and the link is continued. . In the case of the station B, “the partner station time (1:00) ≦ the own station time (5:
00) ", the operation is newer than that of the station A, so that it is dropped from the network without recognizing the priority and the situation of address duplication is avoided.

FIG. 4 is an explanatory diagram showing an embodiment of the third aspect of the present invention. Each station is connected by FDDI and has a broadcast transmission function. The illustrated example shows a case in which a WRAP state is caused by a decrease in light level due to cable deterioration as an abnormal factor. The address 3 stations that detected the abnormality
Set the cause of the error in the frame and broadcast. Even when a frame is lost due to deterioration of the cable, it is always notified after the transmission path is switched for transmission at a fixed period. In addition, by providing a man-machine interface for starting the reception analysis process for each station, it is possible to recognize an abnormality occurring in the entire system from any of the constituent stations.

As described in each embodiment, by dispersing the transmission line load at the time of joining by shifting the transmission timing of the joining request frame, it is possible to eliminate the loss of the frame and reliably detect the abnormality at the time of joining. it can. In addition, by detecting address duplication and judging an overlapping station not only at the time of joining a logical ring but also at an already joined station,
Disturbing the communication of the normal station is prevented. Further, by transmitting broadcast of the notification of the abnormality information at a constant period, it is possible to eliminate a transmission failure due to a missing message. In addition, since all stations can receive abnormality information without setting a specific notification destination to the constituent station of the detection source, any constituent station can recognize an abnormality on the network.

[0017]

As described above, according to the first aspect of the present invention, when a station desiring to join a new station transmits a joining request frame to the network, the station joins from the time when a new joining request is issued to the station itself. The waiting time until the request frame is transmitted is determined using a random number, and after the waiting time, the joining request frame is transmitted. Thus, even if a plurality of new subscriber stations having overlapping addresses desire to join at the same time, the transmission timings of the subscription request frames are shifted from each other, so that only one arbitrary station is reliably subscribed.

According to the second aspect of the present invention, the start-up time of the own station is stored for each station, and the start-up time data of the own station is stored in a frame when a new joining requesting station transmits a join request frame. Sent with addition. In addition, when the address of the already-joined station is the same as the address of the desired station, the start-up time of the own station is compared with the start-up time of the desired station. If it is before the start time of the station, an abnormal response frame is returned from the existing station to the station that wants to join, and if the start time of the existing station is after the start time of the station that wants to join, the existing station returns to the network. Leaves the logical ring. As a result, even if a station with the same address as an existing station wishes to newly join,
A new subscriber is not allowed to join, and existing subscribers are given priority and remain in the logical ring.

According to the third aspect of the present invention, when an address duplication error between a station desiring to join and an already joined station or an abnormality in a transmission line is detected, an abnormality notification frame is created based on the details of the abnormality, Until the detected abnormality is resolved,
Broadcast transmission is performed at a fixed cycle. As a result, even if the abnormality notification frame is lost during transmission, the frame is transmitted again, so that the occurrence of the abnormality is reliably transmitted to another station.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an operation of an exemplary embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an embodiment of the first invention.

FIG. 3 is an explanatory view showing an embodiment of the invention of claim 2;

FIG. 4 is an explanatory view showing an embodiment of the invention of claim 3;

Claims (3)

[Claims] 1. A network for exchanging data between stations that have joined based on a logical ring constituted by stations that have joined the network. If the address of the subscriber station that has received the join request frame is the same as the address of the station that wants to join, it is determined whether the address is the same. In a network that refuses to join by replying from the existing station to the station that wants to join, when a station that wants to join newly sends a join request frame on the network, it joins from the point when a new join request is issued to its own station. Means for determining a waiting time until transmitting the request frame by using a random number, and transmitting the joining request frame after the waiting time has elapsed. Network, characterized in that. 2. A network for exchanging data between each subscribed station based on a logical ring constituted by stations subscribed to the network, wherein a subscribe request frame is transmitted from a subscribed station via the network to a subscribe request frame. If the address of the subscriber station that has received the join request frame is the same as the address of the station that wants to join, it is determined whether the address is the same. In a network that refuses to join by replying to the desired station from the already-subscribed station, means for storing the start-up time of the own station for each station; Means for adding the start-up time data of the station to the frame and transmitting it. When the address of the existing subscriber station is the same as the address of the desired station, the own station is started. Means for comparing the time with the start-up time of the desired station; and, as a result of the comparison, if the start-up time of the already-subscribed station is before the start-up time of the desired station, an abnormal response frame is sent from the previously-subscribed station to the desired station. Means for returning the existing station from the logical ring of the network if the start time of the existing station is after the start time of the desired station. 3. The network according to claim 1 or 2, wherein an address duplication error between a station that desires to join and an already joined station is abnormal.
Means for creating an abnormality notification frame based on the content of the abnormality when an abnormality is detected in the transmission path, and transmitting the created abnormality notification frame at a constant interval until the detected abnormality is resolved. A network, comprising: means for performing broadcast transmission.